Effects of Ageratina adenophora on Spore Germination and Gametophyte Development of Neocheiropteris palmatopedata

2012·4.1 MB·English

by  K M Zhang

Ageratina adenophora on Spore
of
Effects
Germination and Gametophyte Development
of
palmatopedata
Neocheiropteris
M. Zhang and
K. H. Liu
J.
leg ore Res a n
Y- 8-
^
)
^.^^^^^^^^j^^^
Cheng
X.
Zhang
G.
F.
Yunnan Kunming. Yunnan, China
University, 650091,
M. Fang*
Y.
College of Forest Resources and Environment, Nanjing Forestry University, Nanjing, 210037,
China
Jiangsu,
Zhang
H.
J.
China
Nanjing Forestry University, Nanjing, 210037, Jiangsu,
At present, there are about 170 species of terrestrial invasive plants in China.
Ageratina adenophora Sprengel (Synonym: Eupatorium adenophora) (Asteraceae]
Mexico,
a very successful invasive species (Sang et ah, 2010). native to vvrhere
is It is
Yunnan
it is conmion (Cronk and Fuller, 1995). It first invaded Province in China in
the 1940s. Since then has intensively colonized southwest China, reduced
it
community (Wang
and
agricultural production strongly altered plant structures
may
and under and
various conditions
et al, 2011). survives proliferates
It
ZHANG
ET INHIBITION OF AGERATINA ADENOPHORA
AL.: TO NEOCHEIROPTERIS
adversely
affect the surrounding vegetation through
allelopathic China
effects in
(He and Song Yu
Liu, 1990; Yang
et al., 2000; et al, 2004; et al., 2006; Yang et al,
2008).
Most
previous studies of Ageratina adenophora (Ageratina) have focused on
its
deleterious on spermatophytes (Wan
effects
et al, 2010). excretes allelochem-
It
which
icals into the soil, hinder the germination and seedling growth
of potential
competitors (Sang However,
et al, 2010). studies of the adenophora
effects of
/I.
on
invasion
ferns (including gametophytes and
sporophytes) have
received
comparatively
attention (Zhang Zhang
little et al, 2007; et al, 2008a, 2008b).
Yunnan
one
is of the richest regions in species diversity in China (Wang and
Wang,
with documented
2006), 762 (Kunming
fern species
Institute of Botany,
Academy
Chinese
Our
of Sciences, showed
2006). field observations some
that
ferns failed to establish in pure patches of Ageratina adenophora. Previous
by Zhang
studies etal
(2007, 2008a, 2008b) provide strong evidence in support of
the inhibitory effects of A. adenophora on
three fern species, Macrothelypteris
torresiana (Gaud.) Ching, and
Pteris finotii Christ Cibotium harometz Sm.
(L.)
J.
Those showed
studies
that leachates of A. adenophora
all inhibited spore
germination and growth
of the first rhizoid of the three fern species, and
inhibitory increased with
effects increasing leachate
concentrations.
Neocheiropteris palmatopedata
(Baker) H. Christ (Polypodiaceae) endemic
is
China and
to is distributed in Yunnan, Sichuan and Guizhou. well known
It is
ornamental and
for medicinal
value
its (Lin, 2000; Ding, 1982). Furthermore,
in China, it is rare in the wild (Yu, 1999). Hence, understanding the biology of
N. palmatopedata
is of great importance for conservation purposes.
The
distribution of Neocheiropteris palmatopedata
overlaps with
that of
Ageratina adenophora
Yunnan.
in Allelopathic more
activity readily observed
is
in the sensitive stage of plant growth and
(Petersen
Fairbrothers,
1980). In ferns, the
activity is easily detected in stages such as spore germination and gametophyte
development and
(Petersen
Fairbrothers, Hence, study had two main
1980). this
objectives: (i) to determine the potential effects of A. adenophora on spore
germination and gametophyte development
of N. palmatopedata; and
to
(ii)
examine
the
allelopathic potential of stems and
roots, leaves of ^. adenophora.
Plant Leachates
The
effects of Ageratina adenophora on
leachates Neocheiropteris palmatopedata
were
evaluated ways
in three
in this study: 1) rate of rhizoid elongation, rate and
2)
percentage of spore germination, and gametophyte morphology. Whole
3) fresh
plants of A. adenophora were from
collected Nanjing The
Forestry University.
root,
stem and were made
leaf leachates according to Zhang et al (2008a) and were
by them ® PVDF
sterilized passing through Duropore membrane
^m,
(0.45
Carrigtwohill, Co. Cork, For
freland). the determination
of rhizoid
elongation,
the
were
sterile leachates diluted with
sterile double-distilled water
to give six
50%
40 and
For
0, 20, 30, leachate). trials of spore germination
VOLUME NUMBER
AMERICAN FERN JOURNAL:
102 3 (2012)
medium
and gametophyte growth, the leachates were diluted with B5 basal
sterile
2%
(Gamborg et al, 1968] containing 0.7% agar and sugar to give these six con-
2%
medium 0.7% and was
centrations. In all the trials, B5 basal containing agar sugar
mL
cm
used as a control. All media were added at 6 per Petri dish (3.4 diameter).
Spore Germination and Gametophyte Growth
Collection, Incubation,
palmatopedata were from 15-20
Spores of Neocheiropteris collected
fertile
fronds with mature but closed sporangia from 15 individuals on December 2010 in
Yunnan University. The collected fronds were immediately sent to Nanjing. The
and room
fronds were unfolded, placed in clean paper bags air dried at
mm
mesh
temperature. Spores were collected and cleared by a with pores 0.088
Yam
week
in diameter (Zhejiang Shangyu and Sieve Factory, Shangyu, China] one
mg X made
later. About 2 of spores was packed into a 1 1 cm^ bag of clean filter
were immersed water and washed
paper. Thereafter, the spores into distilled live
5%
sodium
times in sterile water after surface-sterilizing in hypochlorite for 4 min.
The spore suspension was prepared by adding sterile double-distilled water to the
sterilized spores. Spores were inoculated evenly in each Petri dish at a density of
and 400 spores/cm^
30 spores/cm^ for the determination of rhizoid elongation for
the of spore germination and gametophyte development. After inoculation,
trials all
cm
Petri dishes were put into larger Petri dishes (12 diameter) to avoid desiccation
and pollution. The larger Pefri dishes were placed in the dark at 25 =C for 24 h and
m"^
1X10^ mol
then transferred to fluorescent light (photon flux density s~^) at
|i
C
25 at 12 h light photoperiod. Five visual fields were observed in each of the Petri
x
dishes, through a gridding ocular a magnification of 20 1.5 in a microscope
at
XTS
Tech
(No. 20130, Beijing Instrument Co., Ltd., Beijing, China).
Germination time was calculated as the time elapsed from sowing to the
when
were
observance of the germinated spore signs of a rhizoid
first (i.e., first
evident). For each dish, fourteen days after the first observed germination, about
400 spores were selected randomly for the calculation of the germination
percentage and also for gametophyte development observation. Thereafter, the
was no was
germination percentage calculated every 6 days until further increase
detected. Data for spore germination and gametophyte assays is presented as the
mean
value of the three Petri dishes of each treatment.
growing weeks
For the determination of rhizoid elongation, after for 2 in
medium
without leachate, six healthy gametophytes with uniform rhizoids in
each dish were selected further observation. Afterwards,
Petri for all
One week
gametophytes were treated with various leachates. later, length of
was micrometer
rhizoid recorded using a crossed ocular in a dissecting
XTS
Tech
microscope (No. 20130, Beijing Instrument Co., Ltd., Beijing, China).
Statistics
The of Ageratina adenophora leachates on spore germination and
effects
gametophyte development Neocheiropteris palmatopedata were analyzed by
of
ANOVA
SPSS USA).
using the 10.0 package (SPSS, Chicago, IL,
0 10 20 30 40
50
Leachate
concentration
(%)
Fig. 1. (iermination time ot the spores of Neocheiropteris palmatopedata
in the control and
with stem and
treated root, leaf leachates of Ageratina adenophora
after inoculation.
Different
<
letters indicate significantly different (P
0.05).
Results
Spore Germination
Spores of Neocheiropteris palmatopedata
germinated
12 days
after inoculation
in
and continued
the control until 35 days. Root, stem and
leaf leachates
of Ageratina
adenophora delayed spore germination. The time needed
for spore germination
among
differed treatments. Spores treated with stem leachates germinated
faster than
and
those treated with root leaf leachates The
(Fig. inhibition of stem and
1). root,
leaf
adenophora
leachates of A. to spore germination percentage of N. palmatopedata
<
increased with increasing concentrations [P As
0.05) time went
(Fig.
2). by, the
germination percentages of N. palmatopedata with
treated the stem and
root,
leaf
adenophora went up and <
leachates of A. then leveled (P
off
0.05) (Fig.
2).
Growth
Rhizoid
and
The stem
leaf leachates of Ageratina adenophora
root,
inhibited
the
growth of Neocheiropteris palmatopedata and
rhizoid the
inhibitory
effect
with
increased increasing
generally leachate concentrations. Root
leachates
most potent followed by <
were the inhibitor, the leaf leachates [P
0.05)
(Fig.
3).
Development
Gametophyte
morphology
Gametophyte of Neocheiropteris palmatopedata
in the
control
was agreement with the previous research carried out by Deng
in
et
al. (2009).

ZHANG
ET
AL.: INHIBITION OF AGERATINA ADENOPHORA TO
NEOCHEIROPTERIS
—
——Stem
^Leaf
——Root
The
gametophytes produced
from
the spores with
treated the leachates of
Ageratina adenophora show
did not
morphological
differences from
the
Discussion
Om-
results indicated that spore germination
of Neocheiropteris palmatopedata
was when
lower
with
treated the stem and
root,
leaf leachates of Ageratina
adenophora
compared
as to the control. Spore germination of N. palmatopedata
is
essential for sexual reproduction.
its germination
If this inhibition also occurs
in
where
nature, spores of N. palmatopedata
overlap with
plants of A. adenophora,
these leachates could
potentially drastically decrease the abundance
of this plant in
the community. The
delay
in germination of N. palmatopedata
spores could
severely
affect the competition
ability of this fern species
for resources.
All leachates of Ageratina adenophora
inhibited rhizoid growth
of Neocheir-
opteris palmatopedata.
Furthermore,
the inhibitory effects increased with the
increasing
leachate
concentrations.
generally believed
It is that the rhizoids of
gametophytes
fern
hinction as organs of uptake and
absorption.
Inhibition of N.
palmatopedata
rhizoid growth by the stem and
root, leaf leachates could reduce
the ability of gametophytes absorb water and which
to
nutrients, could
affect the
production and
growth
potential of the future sporophyte and
function
in the
its
community.
Racusen
demonstrated
(2002) that rhizoids were the primary
of
site
uptake monovalent
for cations in the gametophytes of Onoclea
sensibilis
L.
Kamachi
showed
et al. (2005) that Athyrium gametophytes had
the
ability
to
VOLUME NUMBER
AMERICAN FERN
JOURNAL:
102 3 (2012)
we
accumulate lead in the rhizoids. Therefore, hypothesize that the active
component(s) in the root of A. adenophora entered and accumulated in the
rhizoids of N. palmatopedata, which inhibited the rhizoid elongation of N.
palmatopedata.
palmatopedata
gametophytes produced from the spores of N.
In this study, the
show
adenophora morphological
treated with the leachates of A. did not
differences when compared with the control. However, in a study of Macro-
young gametophytes with various
thelypteris torresiana, the rhizoids of the treated
and and
adenophora were curved, or swollen the curving
root leachates of erect,
v4.
adenophora
swollen rhizoids increased with the increasing concentrations of A.
(Zhang et al, 2008a). The gametophytes from the spores oi Pteris finotii treated with
adenophora morphological
higher concentrations of root leachates of A. suffered
changes (Zhang This difference might be attributed to differences in
et al, 2007).
same
sensitivity to the allelochemicals.
on gametophyte development
In our experiments, greater inhibitory effects
adenophora,
palmatopedata occurred with the root leachates of A.
of N.
was with
as compared to stem and leaf leachates. This result consistent
previous studies, which showed that the root leachates resulted in greater
Zhang
inhibition than the stem and leaf leachates (Zhang et al., 2007; et al,
He
2008a; Tripathi 1981). However, and Liu (1990) observed that the
et
al.,
aqueous leaf extracts of A. adenophora were the most allelopathic to the seed
aqueous
germination of four plants. Tripathi et al. (1981) also reported that the
on
adenophora caused other
extracts of different parts of A. different effects
same
plants. This difference might due to the differences in the sensitivity to
allelochemicals, concentration of the allelochemicals, or variations in al-
among The adenophora were
leachates of A.
lelochemicals the tissues.
phenolic compounds (Yang al, 2006), which might act as the
identified as et
needed
allelopathic substances (Kim et al, 2005). Further investigation is to
understand the chemistry of the allelopathic activity.
better
management adenophora China includes ecological
Sustainable of A. in
and
adenophora
by competitive replacement of A. biological control
restoration
(Wan concern
adenophora Future will the
agents against A. et 2010). efforts
al.,
adenophora well
effective control of A. as as its utilization.
This work was supported by the Priority Academic Program Development of Jiangsu Higher
Education Institutions (PAPD), Jiangsu Planned Projects for Postdoctoral Research Funds
(1001078C) and China Postdoctoral Science Foundation funded project (20100481152).
Literature Cited
Chapman
Cronk, Q. C. B. and L. Fuller. 1995. Plant invaders: the threat to natural ecosystems.
J.
and London, UK.
Hall,
Deng, Y. N., X. Cheng, Y. Jiao and G. Chen. 2009. The gametophyte development and endangerment
J.
mechanism Neocheiropteris palmatopedate (Polypodiaceae, Fern). Acta Bot. Yunnanica.
of